1916 G$1 McKinley PR63 NGC. CAC. Little concrete information
survives concerning the proof McKinley gold dollars. It is clear
that few exist, probably four or five in all. Walter Breen wrote in
his Proof Encyclopedia of four examples, including one in
the Smithsonian Institution.
However, we offered a PR63 Cameo PCGS example in our Chicago
Signature and Platinum Night (Heritage, 8/2011), a piece that
brought $48,875. At that time we published a roster of three
specimens, which included none certified by NGC. We repeat the
roster below, adding the current PR63 NGC example and the August
2011 appearance. We wrote in August 2011:

"Proof examples are extremely rare, with only three
confirmed specimens. Walter Breen recorded a proof in the
Smithsonian Institution, but Jeff Garrett and Ron Guth report that
the Smithsonian coin 'is not a true Proof by today's standards.'
"

As far as we can determine, the addition of the NGC piece below to
the previous roster represents a new discovery of a fourth
piece:

--Choice Proof. RARCOA (Auction '89, 7/1989), lot 363. Part
of a three piece set that also included a business strike and a
nickel trial piece, Judd-1802. This is probably the piece that PCGS
has graded PR64 Cameo, and it appears to be the same piece that is
illustrated in the Garrett and Guth reference.--PR64 PCGS. Superior (10/1990), lot 2283; Superior
(5/1994), lot 1745.--PR63 Cameo PCGS. Bowers and Merena (1/1996), lot 2320;
Stack's (11/2008), lot 5076; Chicago Signature (Heritage, 8/2011),
lot 7718.--PR63 NGC.The present specimen.

The present coin is an unquestionable proof, with razor-sharp
strike details far sharper than any business strike could possibly
show. The surfaces are a medium yellow-gold, incredibly reflective
on each side. A few minor contact ticks appear only a loupe.
Census: 1 in 63, 0 finer (6/12). (PCGS# 7487)